1. Field of the Invention
The present invention relates to a gasoline-ethanol separation apparatus for separating a mixture fuel formed of mixed gasoline and ethanol into gasoline and an ethanol-water mixture liquid by mixing water with the mixture fuel.
2. Description of the Related Art
In recent years, a compression ignition internal combustion engine represented by a homogeneous charge compression ignition internal combustion engine has been investigated so as to enhance a fuel efficiency of an internal combustion engine and reduce emissions. The compression ignition internal combustion engine is an engine of introducing an oxygen-containing gas and a compression self-ignitable fuel into a cylinder, and compressing the mixture gas to self-ignite the mixture gas.
However, the compression ignition internal combustion engine has difficulty in controlling the timing of ignition in contrast to a spark ignition type internal combustion engine, and has a problem that the operation region capable of stably operating the engine is narrow. More particularly, the above described compression ignition internal combustion engine has a problem of easily causing knocking when a high load is required to the engine which uses fuel with high ignitability, and easily causing flame off when a low load is required to the engine which uses fuel with low ignitability.
To solve the above described problem, a compression ignition internal combustion engine is known which comprises a plurality of fuels having different ignitabilities and is controlled by changing an amount of each fuel to be supplied according to the required load. The above described compression ignition internal combustion engine mixes water, for instance, with a single mixture fuel of a liquid hydrocarbon having high ignitability and an alcohol having low ignitability, and thereby separates the resultant mixture into the liquid hydrocarbon and an alcohol-water mixture liquid which has been formed as a result of mixing alcohol with water. The above described compression ignition internal combustion engine is controlled by changing an amount of the mixture fuel to be supplied, an amount of the liquid hydrocarbon to be supplied and an amount of the alcohol-water mixture liquid to be supplied, according to the required load of the engine (See Japanese Patent Laid-Open No. 2006-132368).
A liquid hydrocarbon-ethanol separation apparatus used for the above described compression ignition internal combustion engine is proposed by the applicant of the present invention, which comprises: a first fuel tank for accommodating the mixture fuel formed by mixing the liquid hydrocarbon with ethanol; a water tank for accommodating water to be mixed with the mixture fuel; a second fuel tank for mixing the mixture fuel with water and separating the resultant mixture into the liquid hydrocarbon and an ethanol-water mixture liquid; a third fuel tank for accommodating the separated liquid hydrocarbon; a fourth fuel tank for accommodating the separated ethanol-water mixture liquid; and besides, first to fourth metering pumps which transport the liquids between the water tank and each of the first to fourth fuel tanks (See Japanese Patent Laid-Open No. 2007-46538).
The above described liquid hydrocarbon-ethanol separation apparatus makes the first metering pump supply the above described mixture fuel accommodated in the first fuel tank to the second fuel tank, at first. Subsequently, the second metering pump supplies water accommodated in the water tank to the second fuel tank. Then, water is mixed with the above described mixture fuel in the second fuel tank by being stirred. In the second fuel tank, the ethanol-water mixture liquid is formed by the above described mixing operation, and the ethanol-water mixture liquid is separated from the above described liquid hydrocarbon. Then, the above described liquid hydrocarbon having relatively-small specific gravity forms an upper layer, and the ethanol-water mixture liquid having relatively-large specific gravity forms a lower layer.
Then, the third metering pump supplies the above described liquid hydrocarbon which has been separated from the above described mixture fuel and is accommodated in the second fuel tank to the third fuel tank, and the supplied liquid hydrocarbon is accommodated in the third fuel tank. On the other hand, the fourth metering pump supplies the above described ethanol-water mixture liquid which has been separated from the above described mixture fuel and is accommodated in the second fuel tank to the fourth fuel tank, and the supplied ethanol-water mixture liquid is accommodated in the fourth fuel tank.
The above described liquid hydrocarbon-ethanol separation apparatus can separate the above described mixture fuel into the above described liquid hydrocarbon and the above described ethanol-water mixture liquid, but needs four metering pumps which are considerably heavy, on this account. In addition, in order to take out each of the above described liquid hydrocarbon accommodated in the third fuel tank and the above described ethanol-water mixture liquid accommodated in the fourth fuel tank and supply each of them to the above described compression ignition internal combustion engine, the liquid hydrocarbon-ethanol separation apparatus further needs metering pumps for the third and the fourth fuel tanks. Accordingly, the above described liquid hydrocarbon-ethanol separation apparatus unavoidably makes the weight of the whole apparatus large.
However, in order to be mounted in a mobile unit such as automobile, the above described liquid hydrocarbon-ethanol separation apparatus is desired to be lightweight. For this reason, a liquid hydrocarbon-ethanol separation apparatus is proposed by the applicant of the present invention, which supplies a fuel by controlling an internal pressure in each fuel tank instead of using the above described metering pump (See Japanese Patent Laid-Open No. 2007-56707).
In the liquid hydrocarbon-ethanol separation apparatus, the above described first to fourth fuel tanks and the above described water tank are mutually connected through a liquid-supply pipe having a liquid-supply on-off valve on the way. In addition, the above described first to fourth fuel tanks are each connected to a vacuum pump through an air suction pipe having a suction on-off valve on the way, and respectively include an air open valve.
The above described liquid hydrocarbon-ethanol separation apparatus, at first, makes the above described vacuum pump operated in a state of closing all of the valves; and decompresses the inner part of the second fuel tank by opening a first suction on-off valve provided on the way of a first air suction pipe which connects the above described vacuum pump with the second fuel tank.
Next, the liquid hydrocarbon-ethanol separation apparatus opens a first air open valve provided in the first fuel tank, and simultaneously opens the first liquid-supply on-off valve provided on the way of a first liquid suction pipe which connects the first fuel tank with the second fuel tank to supply the above described mixture fuel accommodated in the first fuel tank to the second fuel tank caused by a pressure difference between the air and the inner part of the second fuel tank. When the predetermined amount of the above described mixture fuel has been supplied to the second fuel tank, the first liquid-supply on-off valve is closed to stop the supply of the above described mixture fuel. The first air open valve is closed after the supply of the above described mixture fuel has been stopped.
Next, the liquid hydrocarbon-ethanol separation apparatus opens a second liquid-supply on-off valve provided on the way of a second air suction pipe for connecting the above described water tank and the second fuel tank to supply water accommodated in the water tank to the second fuel tank caused by a pressure difference between the air and the inner part of the second fuel tank. When the predetermined amount of water has been supplied to the second fuel tank, the second liquid-supply on-off valve is closed to stop the supply of water.
Next, a first air-suction on-off valve is closed, and then, a second air open valve provided in the second fuel tank is opened to return the internal pressure of the second fuel tank to atmospheric pressure. The second air open valve is closed, after the internal pressure of the second fuel tank has been returned to atmospheric pressure.
Subsequently, water is mixed with the above described mixture fuel by being stirred in the second fuel tank. In the second fuel tank, an ethanol-water mixture liquid is formed by the above described mixing operation, and the ethanol-water mixture liquid is separated from the above described liquid hydrocarbon. Then, the above described liquid hydrocarbon having relatively-small specific gravity forms an upper layer, and the ethanol-water mixture liquid having relatively-large specific gravity forms a lower layer.
A second air-suction on-off valve provided on the way of a second air suction pipe which connects the above described vacuum pump with the third fuel tank is opened to decompress the inner part of the third fuel tank. Next, the liquid hydrocarbon-ethanol separation apparatus opens the second air open valve provided in the second fuel tank, and simultaneously opens a third liquid-supply on-off valve provided on the way of a third liquid suction pipe which connects the second fuel tank with the third fuel tank to supply the above described liquid hydrocarbon accommodated in the second fuel tank to the third fuel tank caused by a pressure difference between the inner part of the second fuel tank and the inner part of the third fuel tank. When the predetermined amount of the above described liquid hydrocarbon has been supplied to the third fuel tank, the third liquid-supply on-off valve is closed to stop the supply of the above described liquid hydrocarbon. The second air open valve is closed after the supply of the above described liquid hydrocarbon has been stopped.
Next, the second air-suction on-off valve is closed, and then, a third air open valve provided in the third fuel tank is opened to return the internal pressure of the third fuel tank to atmospheric pressure. The third air open valve is closed, after the internal pressure of the third fuel tank has been returned to atmospheric pressure.
Next, a third air-suction on-off valve provided on the way of a third air suction pipe which connects the above described vacuum pump with the fourth fuel tank is opened to decompress the inner part of the fourth fuel tank. Next, the liquid hydrocarbon-ethanol separation apparatus opens the second air open valve provided in the second fuel tank, and simultaneously opens a fourth liquid-supply on-off valve provided on the way of a fourth liquid suction pipe which connects the second fuel tank with the fourth fuel tank to supply the above described ethanol-water mixture liquid accommodated in the second fuel tank to the fourth fuel tank caused by a pressure difference between the inner part of the second fuel tank and the inner part of the fourth fuel tank. When the predetermined amount of the above described ethanol-water mixture liquid has been supplied to the fourth fuel tank, the fourth liquid-supply on-off valve is closed to stop the supply of the above described ethanol-water mixture liquid. The second air open valve is closed after the supply of the above described ethanol-water mixture liquid has been stopped.
Next, the third air-suction on-off valve is closed, and then, a fourth air open valve provided in the fourth fuel tank is opened to return the internal pressure of the fourth fuel tank to atmospheric pressure. The fourth air open valve is closed, after the internal pressure of the fourth fuel tank has been returned to atmospheric pressure.
Through the above described operations, the above described liquid hydrocarbon separated from the above described mixture fuel is accommodated in the third fuel tank, and the above described ethanol-water mixture liquid separated from the above described mixture fuel is accommodated in the fourth fuel tank. The above described liquid hydrocarbon-ethanol separation apparatus does not use the metering pump, and accordingly can reduce the weight of the whole apparatus.
However, the above described liquid hydrocarbon-ethanol separation apparatus still comprises 5 tanks, so that the whole apparatus unavoidably becomes large. The liquid hydrocarbon-ethanol separation apparatus also combines a switching operation of four air open valves, a switching operation of four liquid-supply on-off valves and a switching operation of three air-suction on-off valves to supply fuel or water by using a difference among internal pressures of a fuel tank of a supply source, a water tank and a fuel tank of a receiving side, so that the structure and the control unavoidably become complicated.
For this reason, the above described liquid hydrocarbon-ethanol separation apparatus is desired to be lightweight, be small and have a simple structure in order to be mounted on a mobile unit such as automobile.